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Transcript of T. Sakai, K. Matsunaga, K. Hoshinoo, ENRI T. Walter, Stanford University T. Sakai, K. Matsunaga, K....
T. Sakai, K. Matsunaga, K. Hoshinoo, ENRIT. Walter, Stanford University
T. Sakai, K. Matsunaga, K. Hoshinoo, ENRIT. Walter, Stanford University
Prototype of SBAS andEvaluation of the Ionospheric
Correction Algorithms
Prototype of SBAS andEvaluation of the Ionospheric
Correction Algorithms
ION NTM 2006ION NTM 2006Monterey, CAMonterey, CA
Jan. 18-20, 2006Jan. 18-20, 2006
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 22
• Implementation of the prototype of SBAS:Implementation of the prototype of SBAS:
– A prototype of SBAS has been successfully implemented;A prototype of SBAS has been successfully implemented;
– Outputs the complete SBAS messages; tested with the Outputs the complete SBAS messages; tested with the
SBAS user receiver simulator;SBAS user receiver simulator;
– The overall performance is comparable with the MSAS.The overall performance is comparable with the MSAS.
• Evaluation of ionospheric correction algorithms:Evaluation of ionospheric correction algorithms:
– Using the above prototype as an evaluation tool;Using the above prototype as an evaluation tool;
– Evaluation of the current algorithm: ‘Planar Fit’; the storm Evaluation of the current algorithm: ‘Planar Fit’; the storm
detector trips a lot during storm ionospheric condition;detector trips a lot during storm ionospheric condition;
– Proposed algorithm with the zeroth order fit reduces the Proposed algorithm with the zeroth order fit reduces the
protection levels to the third part of the current algorithm.protection levels to the third part of the current algorithm.
IntroductionIntroduction
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 33
• MSAS is now under operational test procedures for IOC:MSAS is now under operational test procedures for IOC:
– Protection levels are hugely conservative with large margiProtection levels are hugely conservative with large margi
ns; not reflecting the actual performance;ns; not reflecting the actual performance;
– Needs reducing protection levels to improve availabilityNeeds reducing protection levels to improve availability;;
• However, MSAS has no ‘Testbed’:However, MSAS has no ‘Testbed’:
– There is only the operational system; cannot be used for tThere is only the operational system; cannot be used for t
esting new algorithms;esting new algorithms;
– The prototype of SBAS will be a powerful tool for evaluatiThe prototype of SBAS will be a powerful tool for evaluati
on of new algorithms for improvement of MSAS.on of new algorithms for improvement of MSAS.
• QZSS is being developed in Japan; also needs a testbed for iQZSS is being developed in Japan; also needs a testbed for i
nvestigation of wide-area augmentation technique.nvestigation of wide-area augmentation technique.
MotivationMotivation
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 44
• Actually computer software running on PC and UNIX:Actually computer software running on PC and UNIX:
– ‘‘RTWAD’ written in C language (not MATLAB, sorry);RTWAD’ written in C language (not MATLAB, sorry);
– Consists of the essential components and algorithms of Consists of the essential components and algorithms of
WADGPS;WADGPS;
– Developed for study purpose; does not meet the safety reDeveloped for study purpose; does not meet the safety re
quirements for civil aviation navigation facilities.quirements for civil aviation navigation facilities.
• Generates the complete SBAS messages:Generates the complete SBAS messages:
– Outputs one message per second;Outputs one message per second;
– 250-bit message without FEC encoding;250-bit message without FEC encoding;
– Optional output in NovAtel $FRMA format; works as direct Optional output in NovAtel $FRMA format; works as direct
input to SBAS user receiver simulator.input to SBAS user receiver simulator.
Implemented PrototypeImplemented Prototype
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 55
$FRMA,272,86403.130,138,80811EA4,250,53081FFDFFDFFDFFDFFDFFDFFDFFDFFDFFD$FRMA,272,86403.130,138,80811EA4,250,53081FFDFFDFFDFFDFFDFFDFFDFFDFFDFFDFFDFFDFFFBBBBBBBBBBBBAC1CD280*7CFFDFFDFFFBBBBBBBBBBBBAC1CD280*7C$FRMA,272,86404.130,138,80811EA4,250,9A0C1FFDFFDFFDFFDFFDFFDFFDFFDFFDFFD$FRMA,272,86404.130,138,80811EA4,250,9A0C1FFDFFDFFDFFDFFDFFDFFDFFDFFDFFDFFDFFDFFFBBBBBBBBBBBBB7E76F80*0FFFDFFDFFFBBBBBBBBBBBBB7E76F80*0F$FRMA,272,86405.130,138,80811EA4,250,C661FFDFFDFFDFFDFFDFFFBBBBB880000000$FRMA,272,86405.130,138,80811EA4,250,C661FFDFFDFFDFFDFFDFFFBBBBB8800000000000000000000000000036CD8A40*700000000000000000000036CD8A40*70$FRMA,272,86406.130,138,80811EA4,250,5306FFBFFFF8000000000000000000000000000$FRMA,272,86406.130,138,80811EA4,250,5306FFBFFFF8000000000000000000000000000000000000000000002B963FC0*0D000000000000000002B963FC0*0D$FRMA,272,86407.130,138,80811EA4,250,9A091FFDFFDFFDFFDFFDFFDFFDFFDFFDFFD$FRMA,272,86407.130,138,80811EA4,250,9A091FFDFFDFFDFFDFFDFFDFFDFFDFFDFFDFFDFFDFFFBBBBBBBBBBBB806D3340*77FFDFFDFFFBBBBBBBBBBBB806D3340*77$FRMA,272,86408.130,138,80811EA4,250,C60D1FFDFFDFFDFFDFFDFFDFFDFFDFFDFF$FRMA,272,86408.130,138,80811EA4,250,C60D1FFDFFDFFDFFDFFDFFDFFDFFDFFDFFDFFDFFDFFFBBBBBBBBBBBB924AAE40*08DFFDFFDFFFBBBBBBBBBBBB924AAE40*08$FRMA,272,86409.130,138,80811EA4,250,5361FFDFFDFFDFFDFFDFFFBBBBB890000000$FRMA,272,86409.130,138,80811EA4,250,5361FFDFFDFFDFFDFFDFFFBBBBB89000000000000000000000000000021FE640*7300000000000000000000021FE640*73$FRMA,272,86410.130,138,80811EA4,250,9A61FFDFFDFFDFFDFFDFFFBBBBB8A0000000$FRMA,272,86410.130,138,80811EA4,250,9A61FFDFFDFFDFFDFFDFFFBBBBB8A00000000000000000000000000039994D00*050000000000000000000039994D00*05$FRMA,272,86411.130,138,80811EA4,250,C60A1FFDFFDFFDFFDFFDFFDFFDFFDFFDFFD$FRMA,272,86411.130,138,80811EA4,250,C60A1FFDFFDFFDFFDFFDFFDFFDFFDFFDFFDFFDFFDFFFBBBBBBBBBBBBA6BE8CC0*03FFDFFDFFFBBBBBBBBBBBBA6BE8CC0*03$FRMA,272,86412.130,138,80811EA4,250,530E1FFDFFDFFDFFDFFDFFDFFDFFDFFDFFD$FRMA,272,86412.130,138,80811EA4,250,530E1FFDFFDFFDFFDFFDFFDFFDFFDFFDFFDFFDFFDFFFBBBBBBBBBBBBA99E5040*0AFFDFFDFFFBBBBBBBBBBBBA99E5040*0A
Message Type IDMessage Type ID(6 MSBs)(6 MSBs)
PreamblePreambleMessage Message LengthLength
SBAS Satellite PRNSBAS Satellite PRN
TimeTime
CRCCRC
Message SampleMessage Sample
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 66
• Currently running in offline mode:Currently running in offline mode:
– Used for various evaluation activities;Used for various evaluation activities;
– RINEX observation files are input as monitor station obseRINEX observation files are input as monitor station obse
rvations; provided from GEONET continuous observation rvations; provided from GEONET continuous observation
network operated by GSI, Japan;network operated by GSI, Japan;
– Thus the distribution of monitor stations is variable and thThus the distribution of monitor stations is variable and th
e historical ionospheric storm events can be tested.e historical ionospheric storm events can be tested.
• Utilizes only code phase pseudoranges on dual frequencies:Utilizes only code phase pseudoranges on dual frequencies:
– Needs no carrier measurements;Needs no carrier measurements;
– Outputs one message per second although RINEX is 30-Outputs one message per second although RINEX is 30-
second sampling.second sampling.
Implemented PrototypeImplemented Prototype
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 77User Receiver SimulatorUser Receiver Simulator
• SBAS user receiver simulator:SBAS user receiver simulator:
– Also software running on PC and UNIX;Also software running on PC and UNIX;
– Processes RINEX observation file with L1 pseudorange; cProcesses RINEX observation file with L1 pseudorange; c
arrier smoothing applied;arrier smoothing applied;
– Decodes SBAS message stream (in NovAtel $FRMA recoDecodes SBAS message stream (in NovAtel $FRMA reco
rds) and apply them to the observations;rds) and apply them to the observations;
– Tested with WAAS and MSAS messages.Tested with WAAS and MSAS messages.
• The implemented prototype was evaluated by this simulator:The implemented prototype was evaluated by this simulator:
– With GEONET observations at some locations;With GEONET observations at some locations;
– Output messages work functional;Output messages work functional;
– Evaluates position accuracies and protection levels.Evaluates position accuracies and protection levels.
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 88Monitor StationsMonitor Stations
• We used GEONET sites as We used GEONET sites as monitor stations.monitor stations.
• Dual frequency observation Dual frequency observation sampled every 30 seconds.sampled every 30 seconds.
• 6 monitor stations similar to 6 monitor stations similar to the MSAS.the MSAS.
• 5 user locations for evaluation.5 user locations for evaluation.
GEONET for Monitor StationsGEONET for Monitor Stations
GEONET for User StationsGEONET for User Stations
MSAS Service AreaMSAS Service Area
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 99Example of User Position ErrorExample of User Position Error
• Example of user positioning error Example of user positioning error at Site 940058 (Takayama; near at Site 940058 (Takayama; near center of monitor station networcenter of monitor station network).k).
• Period: 22-24 July 2004; active ioPeriod: 22-24 July 2004; active ionosphere condition.nosphere condition.
Standalone GPSStandalone GPSAugmented by the PrototypeAugmented by the Prototype
HorizontalHorizontalErrorError
VerticalVerticalErrorError
1.929 m1.929 m 3.305 m3.305 m
6.993 m6.993 m 14.48 m14.48 m
SystemSystem
StandaloneStandaloneGPSGPS
0.381 m0.381 m 0.531 m0.531 m
2.867 m2.867 m 5.451 m5.451 mPrototypePrototype
RMSRMS
MaxMax
RMSRMS
MaxMax
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 1010
2005/11/14-162005/11/14-16
HorHor VerVer
2004/7/22-242004/7/22-24
HorHor VerVer
2004/6/22-242004/6/22-24
HorHor VerVer
2005/11/14-162005/11/14-16MSASMSAS
HorHor VerVer
0.3540.3541.6951.695
0.4180.4182.5172.517
0.4320.4322.3182.318
0.5660.5664.4554.455
0.3970.3972.0472.047
0.6020.6024.7174.717
0.3810.3811.6591.659
0.6310.6312.4052.405
0.3040.3041.4871.487
0.4130.4132.1232.123
0.3810.3812.8672.867
0.5310.5315.4515.451
0.4250.4252.6342.634
0.6030.6033.4663.466
0.5020.5024.8734.873
0.7280.7283.7003.700
0.3530.3531.9021.902
0.5080.5084.4524.452
0.4030.4032.4682.468
0.5920.5924.2404.240
0.3850.3851.7571.757
0.6490.6493.7823.782
0.6370.6378.5178.517
0.8810.8819.3969.396
940030940030
940058940058
940083940083
0.4530.4533.3023.302
0.6470.6476.1586.158
0.5860.5862.1432.143
0.7640.7645.5095.509
0.4910.4912.4152.415
0.7760.7764.5744.574
0.6400.6403.0123.012
0.7300.7302.6802.680950491950491
1.1321.1326.2666.266
1.1021.1025.9585.958
080008004.4874.487
1.3171.3179.2259.225
0.7080.7084.5074.507
1.0881.0886.5956.595
0.9820.9826.2676.267
1.0141.0146.6146.6149200392003
RMSRMSMaxMax
RMSRMSMaxMax
RMSRMSMaxMax
RMSRMSMaxMax
RMSRMSMaxMax
SiteSite
NorthNorth
SouthSouth
Performance (Nominal)Performance (Nominal)
Unit: [m]Unit: [m]
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 1111Performance (Severe Storm)Performance (Severe Storm)
2004/11/8-102004/11/8-10
HorHor VerVer
2003/10/29-312003/10/29-31
HorHor VerVer
1.5461.5467.4797.479
1.9001.90011.4411.44
0.9820.9825.6455.645
1.0571.0576.5426.542
1.1571.1577.2217.221
1.5601.5609.2659.265
0.6590.6595.1945.194
0.8400.8406.6526.652
1.0571.0576.3756.375
1.5591.55912.8012.80
1.4071.40714.9014.90
1.8631.86312.3812.38
940030940030
940058940058
940083940083
1.6391.63921.9021.90
2.1952.19523.0923.09
2.1642.16429.4229.42
2.9012.90136.3136.31950491950491
3.3023.30226.8426.84
3.4273.42738.8638.86
3.1213.12115.9315.93
3.3563.35621.6721.679200392003
RMSRMSMaxMax
RMSRMSMaxMax
RMSRMSMaxMax
RMSRMSMaxMax
RMSRMSMaxMax
SiteSite
NorthNorth
SouthSouth
• Large errors due to Large errors due to ionosphere.ionosphere.
• Users still protected within Users still protected within protection levels.protection levels.
Unit: [m]Unit: [m]
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 1212Protection Levels (Quiet)Protection Levels (Quiet)
Protection levelProtection level
Protection level of MSASProtection level of MSAS
Actual errorActual error
• Protection levels during quiet Protection levels during quiet ionosphere at site 950491 ionosphere at site 950491 (second southern user).(second southern user).
• Protects users with large Protects users with large margins.margins.
• MSAS provided further MSAS provided further conservative protection levels.conservative protection levels.
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 1313Protection Levels (Storm)Protection Levels (Storm)
Protection levelProtection level
Actual errorActual error
• Protection levels during storm Protection levels during storm ionosphere at site 950491 ionosphere at site 950491 (second southern user).(second southern user).
• Still protects users with large Still protects users with large margins.margins.
• However protection levels However protection levels grow large; this means low grow large; this means low system availability.system availability.
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 1414
2005/11/14-162005/11/14-16
HorHor VerVer
2004/7/22-242004/7/22-24
HorHor VerVer
2004/6/22-242004/6/22-24
HorHor VerVer
2005/11/14-162005/11/14-16MSASMSAS
HorHor VerVer
20.0220.02 32.1132.11 22.5622.56 33.6933.69 21.7321.73 34.3234.32 25.8225.82 40.4840.48
19.4119.41 32.1832.18 22.0822.08 32.5832.58 27.0027.00 37.6937.69 32.8332.83 46.2946.29
21.6221.62 35.4635.46 23.1323.13 36.9936.99 21.3921.39 37.8237.82 37.6737.67 50.0850.08
940030940030
940058940058
940083940083
28.3728.37 43.9743.97 26.5926.59 41.2441.24 23.1423.14 39.3639.36 44.3444.34 56.2456.24950491950491
55.3455.34 65.3865.38 35.5835.58 56.1156.11 31.3231.32 53.7753.77 85.7985.79 123.0123.09200392003
SiteSite
Nom
inal
Nom
inal
Iono
sphe
reIo
nosp
here
Protection Level StatisticsProtection Level Statistics
2004/11/8-102004/11/8-10
HorHor VerVer
2003/10/29-312003/10/29-31
HorHor VerVer
101.3101.3 152.7152.7 127.7127.7 181.6181.6
91.6191.61 146.0146.0 191.0191.0 231.3231.3
89.7689.76 154.0154.0 152.5152.5 249.5249.5
940030940030
940058940058
940083940083
100.6100.6 167.7167.7 144.0144.0 229.7229.7950491950491
109.5109.5 188.6188.6 129.4129.4 216.9216.99200392003
SiteSite• RMS of protection levels in RMS of protection levels in
meters.meters.
• Grows large for storm Grows large for storm ionospheric conditions.ionospheric conditions.S
ever
e S
torm
Sev
ere
Sto
rmIo
nosp
here
Iono
sphe
re
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 1515ProblemsProblems
• WADGPS Corrections work well:WADGPS Corrections work well:
– Positioning accuracy is 0.3-0.6m horizontal and 0.4-0.8m Positioning accuracy is 0.3-0.6m horizontal and 0.4-0.8m
vertical, respectively, over mainland of Japan;vertical, respectively, over mainland of Japan;
– The largest vertical error was less than 40 meters; could The largest vertical error was less than 40 meters; could
support APV-I operation (HAL=40m, VAL=50m).support APV-I operation (HAL=40m, VAL=50m).
• Protection levels are hugely conservative:Protection levels are hugely conservative:
– HPL and VPL completely protected users;HPL and VPL completely protected users;
– However, protection levels were not reflecting the actual However, protection levels were not reflecting the actual
performance regardless of ionospheric activities;performance regardless of ionospheric activities;
– Needs reducing protection levels to improve availability.Needs reducing protection levels to improve availability.
• Investigates this problem using the prototype system.Investigates this problem using the prototype system.
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 1616VPL during StormVPL during Storm
• Vertical protection levels Vertical protection levels during storm ionosphere at during storm ionosphere at site 950491 (second site 950491 (second southern user) with the southern user) with the baseline algorithm.baseline algorithm.
• Most of VPL came from Most of VPL came from ionospheric component.ionospheric component.
• To reduce protection levels, To reduce protection levels, the primary issue is the primary issue is ionosphere.ionosphere.
Protection levelProtection level
Ionospheric componentIonospheric component
Actual errorActual error
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 1717UIVE and Actual ResidualUIVE and Actual Residual
• UIVE (user ionospheric UIVE (user ionospheric vertical error) is interpolated vertical error) is interpolated from GIVE (grid ionospheric from GIVE (grid ionospheric vertical error).vertical error).
• 5.33 UIVE works as 5.33 UIVE works as ionospheric component of ionospheric component of protection levels.protection levels.
• Large margin even during Large margin even during historical severe storm.historical severe storm.
5.33 UIVE5.33 UIVE
Actual ionosphericActual ionosphericresidualresidual
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 1818
• Without the storm detector Without the storm detector algorithm, UIVE was algorithm, UIVE was computed like this.computed like this.
• The large UIVE in daytime is The large UIVE in daytime is resulted in by trip of storm resulted in by trip of storm detector.detector.
• The actual ionospheric The actual ionospheric residual exceeded 5.33 residual exceeded 5.33 UIVE only once even without UIVE only once even without storm detector.storm detector.
5.33 UIVE5.33 UIVE
Actual ionosphericActual ionosphericresidualresidual
UIVE without Storm DetectorUIVE without Storm Detector
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 1919
• The ionospheric storm detector caused a lot of false alert The ionospheric storm detector caused a lot of false alert
conditions lowering system availability:conditions lowering system availability:
– When storm detector trips, the associate GIVE value is When storm detector trips, the associate GIVE value is
set to the maximum.set to the maximum.
• To avoid such a problem there are two possible ways:To avoid such a problem there are two possible ways:
– Develop an alternative safety mechanism instead of the Develop an alternative safety mechanism instead of the
storm detector;storm detector;
– Develop a method to compute GIVE values instead of Develop a method to compute GIVE values instead of
setting to the maximum when storm detector trips.setting to the maximum when storm detector trips.
• Here we introduce the latter algorithm.Here we introduce the latter algorithm.
Storm Detector ProblemStorm Detector Problem
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 2020
0-th order fit(1 parameter)
Ionosphericdelay
Rmax1-st order fit
(3 parameters)
Estimated delay at IGP
• We can reduce the order of fit when the storm detector We can reduce the order of fit when the storm detector
trips; the planar model cannot be applied.trips; the planar model cannot be applied.
• Only one parameter needs to be estimated; equivalent to Only one parameter needs to be estimated; equivalent to
the weighted average.the weighted average.
• Let us see UIVE and the actual residuals induced by the Let us see UIVE and the actual residuals induced by the
zeroth order fit.zeroth order fit.
Introducing Zeroth Order FitIntroducing Zeroth Order Fit
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 2121UIVE by Zeroth Order FitUIVE by Zeroth Order Fit
• UIVE computed with the UIVE computed with the zeroth order fit without the zeroth order fit without the storm detector algorithm.storm detector algorithm.
• UIVE is larger than planar fit.UIVE is larger than planar fit.
• The largest residual was The largest residual was within 5.33 UIVE even during within 5.33 UIVE even during the historical storm events; the historical storm events; the zeroth order fit does not the zeroth order fit does not need the storm detector.need the storm detector.
5.33 UIVE5.33 UIVE
Actual ionosphericActual ionosphericresidualresidual
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 2222
• The zeroth order fit works well and protects residuals within The zeroth order fit works well and protects residuals within
5.33 UIVE even during storm ionospheric conditions.5.33 UIVE even during storm ionospheric conditions.
• Thus the following adaptive algorithm can be employed:Thus the following adaptive algorithm can be employed:
– 1. Apply the standard planar fit with the storm detector;1. Apply the standard planar fit with the storm detector;
– 2. If storm detector does not trip, employ resulted correcti2. If storm detector does not trip, employ resulted correcti
on and GIVE;on and GIVE;
– 3. Otherwise, or the number of IPPs is insufficient for the 3. Otherwise, or the number of IPPs is insufficient for the
standard planar fit, perform the zeroth order fit.standard planar fit, perform the zeroth order fit.
• This algorithm will reduce the number of IGPs with the maximThis algorithm will reduce the number of IGPs with the maxim
um GIVE due to trip of storm detector.um GIVE due to trip of storm detector.
Adaptive AlgorithmAdaptive Algorithm
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 2323Protection Levels (Storm)Protection Levels (Storm)
• Reduced protection levels to the third part; improved availability.Reduced protection levels to the third part; improved availability.• Still protects users with large margins.Still protects users with large margins.
Baseline AlgorithmBaseline Algorithm Adaptive AlgorithmAdaptive Algorithm
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 2424GIVE StatisticsGIVE Statistics
Baseline algorithmBaseline algorithm
Adaptive algorithmAdaptive algorithm
• Current baseline algorithm pCurrent baseline algorithm produced the maximum GIVE roduced the maximum GIVE (GIVEI=14) for 50% of IGPs.(GIVEI=14) for 50% of IGPs.
• The adaptive algorithm reduThe adaptive algorithm reduced the maximum GIVE conced the maximum GIVE conditions and replaced to GIVEditions and replaced to GIVEI=13.I=13.
GIVEI = 15GIVEI = 15Not MonitoredNot Monitored
GIVEI = 14GIVEI = 14Maximum GIVEMaximum GIVE
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 2525
2004/11/8-102004/11/8-10
HorHor VerVer
2003/10/29-312003/10/29-31
HorHor VerVer
101.3101.327.3127.31
152.7152.741.8341.83
127.7127.732.7332.73
181.6181.648.8848.88
91.6191.6122.9322.93
146.0146.037.3637.36
191.0191.031.3231.32
231.3231.347.8747.87
89.7689.7624.6924.69
154.0154.041.0541.05
152.5152.540.1440.14
249.5249.561.9561.95
940030940030
940058940058
940083940083
100.6100.629.7329.73
167.7167.748.6548.65
144.0144.041.1341.13
229.7229.764.0164.01950491950491
109.5109.538.2638.26
188.6188.665.2165.21
129.4129.444.0144.01
216.9216.973.0073.009200392003
SiteSite
BaselineBaselineAdaptiveAdaptive
BaselineBaselineAdaptiveAdaptive
BaselineBaselineAdaptiveAdaptive
BaselineBaselineAdaptiveAdaptive
BaselineBaselineAdaptiveAdaptive
Reduction of Protection LevelsReduction of Protection Levels
• RMS protection levels RMS protection levels in meters during storm in meters during storm ionospheric conditions.ionospheric conditions.
• The adaptive algorithm The adaptive algorithm reduced protection reduced protection levels to the level of levels to the level of third part of the third part of the baseline algorithm.baseline algorithm.
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 2626
2004/11/8-102004/11/8-10 2003/10/29-312003/10/29-31
38.2 %38.2 %81.7 %81.7 %
29.2 %29.2 %62.8 %62.8 %
37.4 %37.4 %88.2 %88.2 %
26.1 %26.1 %65.9 %65.9 %
39.4 %39.4 %83.3 %83.3 %
15.8 %15.8 %36.8 %36.8 %
940030940030
940058940058
940083940083
38.6 %38.6 %69.6 %69.6 %
20.0 %20.0 %34.3 %34.3 %950491950491
26.3 %26.3 %34.6 %34.6 %
14.0 %14.0 %18.8 %18.8 %9200392003
SiteSite
BaselineBaselineAdaptiveAdaptive
BaselineBaselineAdaptiveAdaptive
BaselineBaselineAdaptiveAdaptive
BaselineBaselineAdaptiveAdaptive
BaselineBaselineAdaptiveAdaptive
LNAV/VNAV AvailabilityLNAV/VNAV Availability
2004/11/8-102004/11/8-10 2003/10/29-312003/10/29-31
37.1 %37.1 %77.6 %77.6 %
28.4 %28.4 %59.0 %59.0 %
36.9 %36.9 %86.8 %86.8 %
25.9 %25.9 %62.1 %62.1 %
39.1 %39.1 %81.6 %81.6 %
15.8 %15.8 %34.9 %34.9 %
38.3 %38.3 %68.7 %68.7 %
19.9 %19.9 %33.9 %33.9 %
25.7 %25.7 %33.8 %33.8 %
14.0 %14.0 %18.7 %18.7 %
APV-I (LPV) AvailabilityAPV-I (LPV) Availability
System AvailabilitySystem Availability
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 2727
• Realtime operation:Realtime operation:
– For implementation and tests integrity functions (TTA);For implementation and tests integrity functions (TTA);
– RTWAD runs with causality to input observations; little moRTWAD runs with causality to input observations; little mo
dification for realtime operation;dification for realtime operation;
– Signal biases will be computed day by day;Signal biases will be computed day by day;
– ENRI is installing realtime monitor stations; 6 stations up tENRI is installing realtime monitor stations; 6 stations up t
o now and one more shortly;o now and one more shortly;
• Evaluation activities in offline mode:Evaluation activities in offline mode:
– Effects of additional monitor stations (IGS stations);Effects of additional monitor stations (IGS stations);
– Testbed for dual frequency SBAS.Testbed for dual frequency SBAS.
Upcoming PlansUpcoming Plans
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 2828Realtime StationsRealtime Stations
• We have already installed 6 stWe have already installed 6 stations with realtime datalink to ations with realtime datalink to ENRI, Tokyo.ENRI, Tokyo.
• Additional station in Toyama is Additional station in Toyama is to be installed shortly.to be installed shortly.
MSAS StationsMSAS Stations
Realtime StatinsRealtime Statins
MSAS Service AreaMSAS Service Area
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 2929Experimental Equipment Experimental Equipment
Trimble 4000SSE in SapporoTrimble 4000SSE in Sapporo
NovAtel MiLLennium and IP convertersNovAtel MiLLennium and IP convertersat ENRI, Tokyoat ENRI, Tokyo
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 3030
• A prototype of SBAS has been successfully implemented:A prototype of SBAS has been successfully implemented:
– Overall accuracy: 0.3-0.6m horizontal and 0.4-0.8m vertical;Overall accuracy: 0.3-0.6m horizontal and 0.4-0.8m vertical;
– Protection levels completely protects users.Protection levels completely protects users.
• Evaluation of ionospheric correction algorithms using prototype:Evaluation of ionospheric correction algorithms using prototype:
– The current algorithm caused a lot of the maximum GIVE;The current algorithm caused a lot of the maximum GIVE;
– Adaptive algorithm will reduce the protection levels to the thirAdaptive algorithm will reduce the protection levels to the thir
d part of the current algorithm and improve availability.d part of the current algorithm and improve availability.• Future works will include:Future works will include:
– Realtime operation of prototype system;Realtime operation of prototype system;
– Simulation of dual frequency SBAS.Simulation of dual frequency SBAS.• Contact: [email protected]: [email protected]
ConclusionConclusion
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 3131Ionospheric Delay: QuietIonospheric Delay: Quiet
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 3232Ionospheric Delay: StormIonospheric Delay: Storm
ION NTM 18-20 Jan. 2006 Sakai, ENRIION NTM 18-20 Jan. 2006 Sakai, ENRI
SSLIDELIDE 3333
MCS Master Control StationMCS Master Control Station
MRSMRS
GMS Ground Monitor StationGMS Ground Monitor Station
Hitachiota MCSHitachiota MCS
Sapporo GMSSapporo GMS
Fukuoka GMSFukuoka GMS
Naha GMSNaha GMS
UserUser
Australia MRSAustralia MRS
Hawaii MRSHawaii MRS
Kobe MCSKobe MCS
Tokyo Tokyo GMSGMS
GPS ConstellationGPS ConstellationMTSATMTSAT
KDD 64KbpsKDD 64Kbps
NTT 64KbpsNTT 64Kbps
1Mbps1Mbps
Monitor and RangingMonitor and RangingStationStation
L-bandL-band
K-bandK-band
Ground LinkGround Link
• 2 GEO2 GEO• 2 MCS2 MCS• 2 MRS2 MRS• 4 GMS4 GMS
MSAS ArchitectureMSAS Architecture